Can it detect tunnels and caves, and if so how deep?

Yes, it has been used successfully to detect and map shallow tunnels, caves, voids, and cavities. With a sample density of approximately 1.25 meters it is unlikely to accurately position targets smaller than 1 meter in lateral dimension. Towing the OhmMapper at speeds of around 1 km/hr will increase sample density and increase the likelihood of detecting shallow targets 50cm in dimension. Detecting voids and cavities deeper than three meters requires them to be larger than one meter.

"...because of the superior customer service, outstanding equipment and performance, and friendly people at Geometrics, that for the past decade I have been a return customer.
- Jean B. Pelletier, M.A. - R.C. Goodwin & Associates, Inc."